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/*
* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang;
import java.lang.StackWalker.StackFrame;
import java.util.EnumSet;
import java.util.Set;
import static java.lang.StackWalker.ExtendedOption.LOCALS_AND_OPERANDS;
/**
* <em>UNSUPPORTED</em> This interface is intended to be package-private
* or move to an internal package.<p>
*
* {@code LiveStackFrame} represents a frame storing data and partial results.
* Each frame has its own array of local variables (JVMS section 2.6.1),
* its own operand stack (JVMS section 2.6.2) for a method invocation.
*
* @jvms 2.6 Frames
*/
/* package-private */
interface LiveStackFrame extends StackFrame {
/**
* Return the monitors held by this stack frame. This method returns
* an empty array if no monitor is held by this stack frame.
*
* @return the monitors held by this stack frames
*/
public Object[] getMonitors();
/**
* Gets the local variable array of this stack frame.
*
* <p>A single local variable can hold a value of type boolean, byte, char,
* short, int, float, reference or returnAddress. A pair of local variables
* can hold a value of type long or double. In other words,
* a value of type long or type double occupies two consecutive local
* variables. For a value of primitive type, the element in the
* local variable array is an {@link PrimitiveValue} object;
* otherwise, the element is an {@code Object}.
*
* @return the local variable array of this stack frame.
*/
public Object[] getLocals();
/**
* Gets the operand stack of this stack frame.
*
* <p>
* The 0-th element of the returned array represents the top of the operand stack.
* This method returns an empty array if the operand stack is empty.
*
* <p>Each entry on the operand stack can hold a value of any Java Virtual
* Machine Type.
* For a value of primitive type, the element in the returned array is
* an {@link PrimitiveValue} object; otherwise, the element is the {@code Object}
* on the operand stack.
*
* @return the operand stack of this stack frame.
*/
public Object[] getStack();
/**
* <em>UNSUPPORTED</em> This interface is intended to be package-private
* or move to an internal package.<p>
*
* Represents a local variable or an entry on the operand whose value is
* of primitive type.
*/
public abstract class PrimitiveValue {
/**
* Returns the base type of this primitive value, one of
* {@code B, D, C, F, I, J, S, Z}.
*
* @return Name of a base type
* @jvms table 4.3-A
*/
abstract char type();
/**
* Returns the boolean value if this primitive value is of type boolean.
* @return the boolean value if this primitive value is of type boolean.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type boolean.
*/
public boolean booleanValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the int value if this primitive value is of type int.
* @return the int value if this primitive value is of type int.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type int.
*/
public int intValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the long value if this primitive value is of type long.
* @return the long value if this primitive value is of type long.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type long.
*/
public long longValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the char value if this primitive value is of type char.
* @return the char value if this primitive value is of type char.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type char.
*/
public char charValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the byte value if this primitive value is of type byte.
* @return the byte value if this primitive value is of type byte.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type byte.
*/
public byte byteValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the short value if this primitive value is of type short.
* @return the short value if this primitive value is of type short.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type short.
*/
public short shortValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the float value if this primitive value is of type float.
* @return the float value if this primitive value is of type float.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type float.
*/
public float floatValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
/**
* Returns the double value if this primitive value is of type double.
* @return the double value if this primitive value is of type double.
*
* @throws UnsupportedOperationException if this primitive value is not
* of type double.
*/
public double doubleValue() {
throw new UnsupportedOperationException("this primitive of type " + type());
}
}
/**
* Gets {@code StackWalker} that can get locals and operands.
*
* @throws SecurityException if the security manager is present and
* denies access to {@code RuntimePermission("liveStackFrames")}
*/
public static StackWalker getStackWalker() {
return getStackWalker(EnumSet.noneOf(StackWalker.Option.class));
}
/**
* Gets a {@code StackWalker} instance with the given options specifying
* the stack frame information it can access, and which will traverse at most
* the given {@code maxDepth} number of stack frames. If no option is
* specified, this {@code StackWalker} obtains the method name and
* the class name with all
* {@linkplain StackWalker.Option#SHOW_HIDDEN_FRAMES hidden frames} skipped.
* The returned {@code StackWalker} can get locals and operands.
*
* @param options stack walk {@link StackWalker.Option options}
*
* @throws SecurityException if the security manager is present and
* it denies access to {@code RuntimePermission("liveStackFrames")}; or
* or if the given {@code options} contains
* {@link StackWalker.Option#RETAIN_CLASS_REFERENCE Option.RETAIN_CLASS_REFERENCE}
* and it denies access to {@code StackFramePermission("retainClassReference")}.
*/
public static StackWalker getStackWalker(Set<StackWalker.Option> options) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(new RuntimePermission("liveStackFrames"));
}
return StackWalker.newInstance(options, LOCALS_AND_OPERANDS);
}
}